external moisture

Compliance Document for New Zealand Building Code Clause E2 External MoisturePrepared by the Department of Building and Housing

This Compliance Document is prepared by the Department of Building and Housing. The Department of Building and Housing is a Government Department established under the State Sector Act 1988. Enquiries about the content of this document should be directed to:

Department of Building and Housing PO Box 10-729, Wellington. Telephone 0800 242 243 Fax 04 494 0290 Email: [email protected] Compliance Documents are available from www.dbh.govt.nz

Department of Building and Housing 2011 This Compliance Document is protected by Crown copyright, unless indicated otherwise. The Department of Building and Housing administers the copyright in this document. You may use and reproduce this document for your personal use or for the purposes of your business provided you reproduce the document accurately and not in an inappropriate or misleading context. You may not distribute this document to others or reproduce it for sale or profit. The Department of Building and Housing owns or has licences to use all images and trademarks in this document. You must not use or reproduce images and trademarks featured in this document for any purpose (except as part of an accurate reproduction of this document) unless you first obtain the written permission of the Department of Building and Housing.

Status of Compliance Documents Compliance Documents are prepared by the Department of Building and Housing in accordance with section 22 of the Building Act 2004. A Compliance Document is for use in establishing compliance with the New Zealand Building Code. A person who complies with a Compliance Document will be treated as having complied with the provisions of the Building Code to which the Compliance Document relates. However, a Compliance Document is only one method of complying with the Building Code. There may be alternative ways to comply. Users should make themselves familiar with the preface to the New Zealand Building Code Handbook, which describes the status of Compliance Documents and explains alternative methods of achieving compliance. Defined words (italicised in the text) and classified uses are explained in Clauses A1 and A2 of the Building Code and in the Definitions at the start of this Compliance Document. E2: Document HistoryDate First published Second Edition Third Edition Amendment 1 September 2004 July 1992 28 February 1998 E2/VM1 effective from 1 July 2004 E2/AS1 effective from 1 February 2005 E2/AS1 effective from 1 July 2005 p. 2 Document Status Document revised Second edition issued Alterations

Reprinted incorporating Amendment 1 September 2004 Amendment 2 Effective from 1 July 2005 p. 2 Document History, Document Status pp. 5-7, 9, 10 Contents pp. 13-16 References pp. 17-20 Definitions pp. 21-24 E2/VM1 p. 166 Table 23 pp. 3 and 4, Building Code Clause E2 p. 2 Document History, Document Status pp. 8 and 12 Contents pp. 13-14 References p. 2 Document History, Document Status pp. 5-12 Contents pp. 13-16A References pp. 17-20 Definitions pp. 21-24 E2/VM1 p. 2 Document History, Document Status p. 9 Contents pp. 171-180 E2/AS2 p. 181 Index pp. 25-180 E2/AS1 pp. 183-184,189-190 E2/AS2 p. 191 E2/AS3 pp. 193-204 Index pp. 29, 41, 43, 49, 55-57, 80, 81, 87, 91, 93, 94, 101, 106-108, 110-115, 117, 158, 160, 172, 176, 191 E2/AS1 pp. 25-43, 45-47, 49, 50, 55-57, 59-67, 69-89, 93-100, 102, 103, 105-107, 111-119, 121-125, 127-135, 138, 140-144, 146, 147, 149, 150, 153-155, 157,163-169 E2/AS1 pp. 173, 174, 177, 178 Index

Erratum 1 Amendment 3 Amendment 4

Effective from 1 December 2005 21 June 2007 Effective from 1 May 2008 until 31 January 2012

Amendment 5

1 August 2011

Errata 2

24 December 2011

Document Status The most recent version of this document, as detailed in the Document History, is approved by the Chief Executive of the Department of Building and Housing. E2 External Moisture Document Amendment 5 Errata 2 supersedes all previous versions from 1 February 2012, except for special provisions outlined in E2/VM1 Paragraph 1.5. E2 External Moisture Document Amendment 4 may also be used until 31 January 2012, except for special provisions outlined in E2/VM1 Paragraph 1.5 Amendment 5. People using this Compliance Document should check for amendments on a regular basis. The Department of Building and Housing may amend any part of any Compliance Document at any time. Up-to-date versions of Compliance Documents are available from www.dbh.govt.nz

Clause E2

EXTERNAL MOISTURE

New Zealand Building Code Clause E2 External MoistureThis Clause is extracted from the New Zealand Building Code contained in the First Schedule of the Building Regulations 1992.

SR2007/124

Clause E2External moistureProvisions ObjectiveE2.1 The objective of this provision is to safeguard people from illness or injury that could result from external moisture entering the building. Functional requirement E2.2 Buildings must be constructed to provide adequate resistance to penetration by, and the accumulation of, moisture from the outside. Requirement E2.2 does not apply to buildings (for example, certain bus shelters, and certain buildings used for horticulture or for equipment for washing motor vehicles automatically) if moisture from the outside penetrating them, or accumulating within them, or both, is unlikely to impair significantly all or any of their amenity, durability, and stability.

Limits on application

Performance E2.3.1 Roofs must shed precipitated moisture. In locations subject to snowfalls, roofs must also shed melted show. E2.3.2 Roofs and exterior walls must prevent the penetration of water that could cause undue dampness, damage to building elements, or both. E2.3.3 Walls, floors, and structural elements in contact with, or in close proximity to, the ground must not absorb or transmit moisture in quantities that could cause undue dampness, damage to building elements, or both. E2.3.4 Building elements susceptible to damage must be protected from the adverse effects of moisture entering the space below suspended floors. E2.3.5 Concealed spaces and cavities in buildings must be constructed in a way that prevents external moisture being accumulated or transferred and causing condensation, fungal growth, or the degradation of building elements.

Amend 3 Jun 2007

D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G

21 June 2007

3

EXTERNAL MOISTURE

C lause E2

SR2007/124

ProvisionsPerformance E2.3.6 Excess moisture present at the completion of construction must be capable of being dissipated without permanent damage to building elements. E2.3.7 Building elements must be constructed in a way that makes due allowance for the following: (a) the consequences of failure: (b) the effects of uncertainties resulting from construction or from the sequence in which different aspects of construction occur: (c) variation in the properties of materials and in the characteristics of the site.

Limits on application

Amend 3 Jun 2007

4

21 June 2007


C o n t e n ts E 2 /VM1 & AS1 /AS2 /AS3

EXTERNAL MOISTURE

ContentsPage References Definitions Verification Method E2/VM1 1.0 13 17 21 1.4 1.5 2.0 2.1 2.2 2.3 2.4 2.5 3.0 3.1 Specific design Qualifications General Weathertightness Materials Systems versus materials Cladding finish colours Maintenance general Weathertightness Risk Factors Establishing the risk 26 26 26 26 26 26 26 27 27 27 27 27 27 28 32 32 33 34 35 35 35 35 36 36 36 36 36 37 37 37 37 37 37Amend 5 Aug 2011 Amend 5 Aug 2011 Amend 2 Jul 2005

Cladding systems of buildings, 21 including junctions with windows, doors and other penetrations General Scope Specimen details Test procedure 21 21 21 22 22 22 22 22 23 23

1.1 1.2 1.3 1.4

2.5.1 Regular maintenance

1.4.1 PreconditioningAmend 2 Jul 2005

3.1.1 Definitions of risk 3.1.2 The risk score 3.3 3.4 Wall claddings Examples using the risk matrix

1.4.2 Series 1 Static pressure water penetration 1.4.3 Series 1 Cyclic pressure water penetration 1.4.4 Series 2 'Water management testing'

Amend 2 Jul 2005

3.4.1 Example 1 3.4.2 Example 2 3.4.3 Example 3 4.0 4.1 4.2 Flashings Materials for flashings Selection of flashing materials

Amend 5 Aug 2011

1.4.5 Series 3 'Wetwall test' 1.5 Transition period for existing verification certificates as at 31 August 2011 Pro-forma for test details Pitched roofing systems over a ventilated roof space of 15 pitch or more Skillion roofs and commercial and industrial roofing Appendix 1: Pro forma Acceptable Solution E2/AS1 1.0 1.1 Scope Construction included Attached garages Construction excluded

Amend 2 Jul 2005

1.6 2.0

23 23 4.2.1 Environment 4.2.2 Surrounding materials 4.3 Acceptable flashing materials 4.3.1 uPVC flashings 4.3.2 Aluminium flashings 4.3.3 Galvanized steel flashings 4.3.5 Stainless steel flashings 4.3.6 Copper flashings 4.3.7 Lead sheet flashings 4.3.8 Zinc sheet flashings 4.3.9 Butyl rubber and EPDM flashings 4.3.10 Bituminous flashings

3.0

23 24 25 25 25 25 25 25 25 25 25

4.3.4 Aluminium-zinc coated steel flashings 36

Amend 5 Aug 2011

1.1.1 1.2

1.2.1 Outbuildings 1.2.2 Spread of flameAmend 2 Jul 2005

1.2.3 Acoustics 1.3 Provisions for snow


1 August 2011

5

EXTERNAL MOISTURE

C ontents

4.3.11 Flexible flashing tape 4.4 4.5 Fixings Flashing requirements

37 37 37 37 38 39 39 42 42 44 44 45 45 45 45 47 48 48 48 51 51 51 51 51 51 52 54 54 54 57 57 57 57 57 58 59 59 59

8.1.2 Limitations 8.1.3 Maintenance 8.1.4 Fixings 8.1.5 Roof underlays 8.1.6 Gutters general 8.1.7 Roof penetrations 8.2 Masonry Tiles 8.2.1 Materials 8.2.2 General 8.2.3 Installation 8.2.4 Flashings and fixings 8.2.5 Anti-ponding boards 8.2.6 Details and flashings 8.2.7 Penetrations 8.3 Pressed Metal Tiles 8.3.1 Limitations 8.3.2 Installation 8.3.3 Tiles 8.3.4 Metal substrate 8.3.5 Roof pitch 8.3.6 Underlay 8.3.7 Fixings 8.3.8 Flashings 8.3.10 Roof penetrations 8.4 Profiled Metal Roof Cladding 8.4.1 Limitations 8.4.2 General 8.4.3 Materials 8.4.4 Profiles 8.4.5 Roof pitch 8.4.6 Structure 8.4.7 Underlay 8.4.8 Fixings: corrugated and trapezoidal 8.4.9 Fixings: trough profile 8.4.10 Allowance for expansion 8.4.11 Flashing requirements

59 59 59 59 60 61 63 63 63 63 63 63 63 66 68 68 68 68 68 68 69 69 69 72 73 73 73 73 74 74 74 76 76 78 78 78Amend 5 Aug 2011 Amend 2 Jul 2005

4.5.1 Edge treatments for flashings 4.5.2 Metal flashing joints 4.6 5.0 5.1 5.2 5.3 6.0 6.1 6.2 6.3 6.4 6.5 6.6 7.0 7.1 Flashing overlaps and upstands Roof/Wall Junctions Apron flashings Gutters, barges and fascias Soffits Parapets Limitations General Capping materials Metal cappings Membrane cappings Integral surface cappings Decks and Pergolas Thresholds for decks 4.6.1 Overlap with roof claddings

6.4.1 Parapet-to-wall junctions

7.1.1 Slatted decks 7.1.2 Enclosed decks 7.2 Attachment to building structure 7.2.1 Slatted timber decks to walls 7.2.2 Pergolas 7.3 Level threshold 7.3.1 Enclosed decks 7.3.2 Ground floor level access 7.4 Enclosed balustrades 7.4.1 Deck drainage 7.4.2 Balustrade-to-wall junctions 7.4.3 Balustrade-to-deck floor junction 7.4.4 Metal cappings 7.4.5 Stanchions 8.0Amend 5 Aug 2011

8.3.9 Gutters, ridges, barges and fascias 72

Roof Claddings General

8.1

8.1.1 Weathertightness

6

1 August 2011


C o n t e n ts

EXTERNAL MOISTURE

8.4.12 Flashing details 8.4.13 Stopends 8.4.14 Turn-downs at gutters 8.4.15 Profile closure 8.4.16 Hidden, valley and internal gutters 8.4.17 Roof penetrations 8.5 Membrane Roofs and Decks 8.5.1 Limitations 8.5.2 General 8.5.3 Plywood substrates 8.5.4 Butyl and EPDM 8.5.5 Installation 8.5.6 Roof and deck drainage 8.5.7 Control joints 8.5.8 Junctions 8.5.9 Penetrations 8.5.10 Gutters 9.0 9.1 Wall Claddings General

79 84 84 84 84 86 89 89 89 89 89 90 90 91 92 92 93 97 97 97 97 97 98 99 99 99 100 101 103 108 108 108 108 108 113 113 114

9.2.8 Control joints 9.2.9 Openings in masonry veneer 9.2.10 Windows and doors 9.2.11 Secondary cladding 9.3 Stucco 9.3.1 Limitations 9.3.2 Structure 9.3.3 Stucco cladding system 9.3.4 Installation 9.3.5 Non-rigid plaster backings 9.3.6 Rigid plaster backings 9.3.7 Finishes 9.3.8 Bottom of stucco

115 115 116 116 117 117 117 117 117 118 118 118 118

9.3.9 Parapets and enclosed balustrades 118 9.3.10 Windows and doors 9.4 Timber Weatherboards 9.4.1 Limitations 9.4.2 Materials 9.4.3 Installation 9.4.4 Horizontal weatherboards 9.4.5 Vertical weatherboards 118 121 121 121 121 121 124

9.1.1 Limitations 9.1.2 Maintenance 9.1.3 Bottom of cladding 9.1.4 Barriers to airflow 9.1.5 Wall underlays to wall openings 9.1.6 Air seals 9.1.7 Wall underlay 9.1.8 Drained cavities 9.1.9 Penetrations 9.1.10 Windows and doors 9.2 Masonry Veneer 9.2.1 Limitations 9.2.2 General 9.2.3 Installation 9.2.4 Flashings 9.2.5 Foundation support and damp proofingAmend 5 Aug 2011

9.4.6 Windows and doors in direct fixed 125 weatherboards 9.4.7 Windows and doors in cavity walls 125 9.4.8 Parapets and enclosed balustrades 132 9.4.9 Finishes 9.5 Fibre Cement Weatherboards 9.5.1 Limitations 9.5.2 Material performance 9.5.3 Installation 9.5.4 Windows and doors 9.5.6 Protective coating 9.6 Profiled Metal Wall Cladding 9.6.1 Limitations 9.6.2 General 9.6.3 Materials 132 133 133 133 133 134 134 138 138 138 138Amend 5 Aug 2011 Amend 2 Jul 2005

9.5.5 Parapets and enclosed balustrades 134

9.2.6 Cavities 9.2.7 Wall ties


1 August 2011

7

EXTERNAL MOISTURE

C ontents

9.6.4 Maintenance 9.6.5 Profiles 9.6.6 Fixing 9.6.7 Flashings 9.6.8 Vertical profile direct fixed 9.7 Fibre Cement Sheet

138 139 139 139 139 148 148 148 148 152 153 153 159 160 160 160 160 161 161 161 161 161 163 163 163 163 163 165 165 166 166 167 Acceptable Solution E2/AS2 1.0 1.1 1.0 Earth buildings Modifications to NZS 4299 181 181 181 191 10.0 10.1 10.2 10.3 Construction Moisture Moisture in materials Maximum acceptable moisture contents Measuring moisture content 171 171 171 171 171 171

Amend 5 Aug 2011

9.6.9 Horizontal profiled metal on cavity 143 9.7.1 Limitations 9.7.2 Material and installation both systems 9.7.3 Jointed systems 9.7.4 Flush-finished systems 9.7.5 Soffit details 9.7.6 Windows and doors 9.7.8 Decorative attachments 9.8 Plywood Sheet


10.3.1 Timber 10.3.2 Concrete floors

9.8.1 Limitations 9.8.2 Materials 9.8.3 Installation 9.8.4 Corners 9.8.5 Flashing material 9.8.6 Soffit details 9.8.8 Windows and doors 9.8.9 Finishes 9.9 EIFS 9.9.1 Limitations 9.9.2 General 9.9.3 Materials 9.9.4 Installation 9.9.5 Battens 9.9.6 Coating 9.9.7 EIFS/floor slab junction 9.9.8 Pipes and service penetrationsAmend 5 Aug 2011


Amend 4 May 2008

Acceptable Solution E2/AS3

Concrete and concrete masonry 191 buildings

9.9.9 Windows and doors


8

1 August 2011


C o n t e n ts

EXTERNAL MOISTURE

TablesAmend 5 Aug 2011

Table 18B: Placement of wall ties 29 30 31 33 34 40 61 62 63 75 Table 18C: Corrosion protection to masonry wall ties Table 18D: Corrosion protection to lintels Table 18E: Masonry veneer lintel sizes (minimum) Table 19: Control joints for flush-finished fibre cement Table 20: Material selection Table 21: Compatibility of materials in contact Table 22: Compatibility of materials subject to run-off Table 23: Properties of roof underlays and wall underlays Table 24: Fixing selection for wall claddings Figures Figure 1: How to assess risk 75 Figure 2: Risk matrix example 1 Figure 3: Risk matrix example 2 Figure 4: Risk matrix example 3 Figure 5: Typical metal flashing edge treatments Figure 6: Joints in metal flashings Figure 7: Basic apron flashing Figure 8A: Soffit/wall junction Figure 8B: Gutter/wall junction

114 115 115 116

Table 1: Definitions of risk levies Table 2: Building envelope risk matrix Table 3: Suitable wall claddings Table 5: Risk matrix example 2 south elevation Table 6: Risk matrix example 3 south elevation Table 7: Metal flashings general dimensions Table 8: Maximum catchment areas for valley gutters Table 9: Maximum catchment areas above penetrations Table 10: Minimum pitches for masonry tiles Table 11: Steel corrugate profiled roofing 0.4 mm BMT and minimum profile height 16.5 mm Table 12: Steel corrugate profiled roofing 0.55 mm BMT with minimum profile height 16.5 mm

Table 4: Risk matrix example 1 south face 32

153 172 174 175 176 177

Errata 2 Dec 2011

28 32 33 34 38 38 42 43 44

Amend 2 Jul 2005

Table 13: Steel trough profile roofing 76 0.55 mm BMT with profile height 46 mm minimum, and pan width 210 mm maximum Table 14: Steel trapezoidal profiled roofing 77 0.4 mm BMT and profile height 27 mm minimum and minimum 5-rib profiles Table 15: Steel trapezoidal profiled roofing 77 0.55 mm BMT, profile height 27 mm minimum and minimum 5-rib profiles Table 16: Expansion provisions Table 17: Catchment areas for profiled metal Table 18: Minimum clearances 78 86 97

Figure 9: General capping joints for 46 parapets and enclosed balustrades Figure 10: General construction of 47 parapet and enclosed balustrade Figure 11: Parapet/enclosed balustrade49 to-wall junctions plan section Figure 12: General junction of parapet 50 and enclosed balustrade to wall

Errata 2 Dec 2011

Table 18A: Specifications of maximum tie 114 spacings for type B veneer ties

Figure 14: Threshold separations Figure 15: Junction with wall for noncantilevered timber deck

51 52Amend 5 Aug 2011


24 December 2011

9

EXTERNAL MOISTURE

C ontents

Figure 16: Junction with wall for cantilevered timber deck Figure 17A:Level thresholds for enclosed decks Figure 17B:Level thresholds for ground level Figure 17D:Door sills for direct fix Figure 18: Enclosed balustrade bottom of cladding Figure 19: Stanchion fixing Figure 20: Spreader for roof discharge Figure 21: Penetration support Figure 23: Masonry tile ridgeAmend 2 Jul 2005

53 55 56

Figure 43: Ridge to hip flashings Figure 44: Apron flashing and change in pitch for profiled metal Figure 45: Eaves and roof/wall ridge for profiled metal Figure 46: Ridge and hip flashings for profiled metal Figure 48: Parallel apron flashings for profiled metal Figure 49: Profiled metal stopends Figure 50: Parallel hidden gutter for profiled metal

80 80 81 81

Figure 17C:Door sills for cavity construction 56A 56B 57 58 60 62 64 64 65 65 66

Figure 47: Barge flashings for profiled metal 82 83 84 85Amend 2 Jul 2005

Figure 22: Catchment area for penetrations 62 Figure 24: Barge for masonry tile Figure 25: Timber fascia eaves for masonry tile Figure 26: Apron details for masonry tile Figure 27: Valley for masonry tile

Figure 51: Valley gutters for profiled metal 85 Figure 52: Internal gutter for profiled metal 86 Figure 53: Flashing for small pipes Figure 54: Soaker flashing for pipe penetrations Figure 55: Soaker flashing for other penetrations Figure 56: Falls in membrane roofs and decks Figure 57: External corner in upstand Figure 58: Internal corner in upstand Figure 60: Pipe penetration in membrane Figure 61: Verges in membrane Figure 63: Rainwater head and scupper opening in membrane Figure 65: Levels and garage openings Figure 66: Cavity base closer/vermin proofing Figure 67: Cavity spacers Figure 68: General pipe penetration Figure 69: General meterbox and similar penetrations Figure 70: General inter-storey junction 87 87 88 91 91 92 92 93 95

Figure 28: Roof/wall ridge for masonry tile 66 Figure 29: Pipe penetration for masonry tile 66 Figure 30: Abutment at framed penetration 67 for masonry tile Figure 31: Flashing to framed penetration for masonry tile Figure 32: Metal tile profiles Figure 33: Metal tile fixings Figure 34: Ridge or hip flashings for metal tile Figure 35: Apron flashings for metal tile Figure 36: Eaves and barge for metal tile Figure 37: Hidden and valley gutter flashings for metal tile Figure 38: Profiled metal profiles 67 68 69 70 70 71 71 74

Figure 59: Roofing penetration in membrane 92

Figure 62: Junctions with walls for membrane 94

Figure 64: Gutters and outlets in membrane 96 97 100 100 102 103 103Amend 5 Aug 2011

Figure 39: Corrugated and trapezoidal fixings and sheet lap 77Amend 2 Jul 2005 Amend 5 Aug 2011

Figure 40: Typical trough profile fixings Figure 41: Soft edge flashing Figure 42: Trapezoidal notched flashing

78 79 79

Figure 71: General sealing of head flashing 104

10

1 August 2011


C o n t e n ts

EXTERNAL MOISTURE

Figure 72A: General window and door opening for direct fixed Figure 72B: General window and door opening with drainage cavity Figure 73A: Vertical control joint Figure 73B: Masonry veneer height limitations Figure 73C: Masonry veneer window and door installation Figure 73D: Masonry veneer details Figure 73E: Masonry veneer details Figure 74: Types of stucco cladding Figure 75: Bottom of stucco cladding Figure 76: Windows and doors in stucco cladding

106 107 108 109 110 111 112 117 119 120

Figure 89: Aluminium corners in fibre cement weatherboards Figure 90: Windows and doors in fibre cement direct fixed weatherboards

135 136

Figure 91: Windows and doors in fibre 137 cement weatherboards on cavity Figure 92: Barge for vertical profiled metal 140 Figure 93: Bottom of cladding for vertical 140 profiled metal Figure 94: Corners for vertical profiled metal 141

Figure 95: Windows and doors for vertical 142 profiled metal Figure 96: Corner flashings for horizontal 143 profiled metal Figure 97: Barge for horizontal profiled metal Figure 98: Bottom of cladding Figure 99: Windows and doors for horizontal profiled metal on cavity Figure 100: Window and door flashings for profiled metal Figure 101: Balustrade for vertical profiled metal Figure 102: Balustrade for horizontal profiled metal 144 144 145

Figure 77: Corner soakers for bevel-back 122 weatherboards Figure 78: External corners for horizontal 123 weatherboards Figure 79: Internal corners for horizontal or vertical weatherboards Figure 80: External corners for vertical weatherboards 124 125

146 147 147

Figure 81: Windows and doors for direct 126 fixed bevel-back weatherboards Figure 82: Windows and doors for direct 127 fixed rusticated weatherboards Figure 83: Windows and doors for direct fixed vertical shiplap weatherboards Figure 84: Windows and doors for direct fixed board and batten weatherboards 128

Figure 104A: Vertical uPVC joints for fibre 149 cement sheet Figure 104B: Internal corners for fibre cement sheet Figure 105: Vertical timber batten joints for fibre cement sheet Figure 107: Horizontal joints for direct fixed fibre cement Figure 108: Horizontal joints for fibre cement sheet on cavity Figure 110: Flush-finished joints for fibre cement sheet 149 150

129

Figure 85: Windows and doors for bevel- 130 back weatherboards on cavity Figure 86: Windows and doors for rusticated weatherboards on cavity Figure 87: Joints in fibre cement weatherboardsAmend 5 Aug 2011

131

151 152

133 134

Figure 88: External corners in fibre cement weatherboards

1 53

Amend 5 Aug 2011


1 August 2011

11

EXTERNAL MOISTURE

C ontents

Figure 111: Vertical movement control joint for flush-finished fibre cement sheet

154

Figure 113: Flush-finished external corners 155 for fibre cement sheet Figure 114: Soffits for flush-finished fibre cement sheet 155 Figure 115: Windows and doors for direct 156 fixed fibre cement sheet Figure 116: Windows and doors for fibre 157 cement sheet and flush-finished fibre cement on cavity Figure 117: Enclosed balustrade to wall for fibre cement sheet 158

Figure 9.2: Head details A) Timber joinery with timber-framed wall insert B) Aluminium joinery with timber-framed wall insert C) Timber joinery with timber lintel D) Aluminium joinery with timber lintel Figure 9.3: Jamb details A) Timber joinery B) Aluminium joinery Figure 9.4: Sill details A) Timber joinery with brick or tile sill B) Aluminium joinery with brick or tile sill C) Timber joinery with concrete sill D) Aluminium joinery with concrete sill

185 185 185 186 186 187 187 187 188 188 188 189 189Amend 4 May 2008

Figure 119: Battened joints for plywood 160 sheet Figure 121: Horizontal joints for plywood 161 sheet Figure 122: External corners for plywood 162 sheet Figure 123: Internal corners for plywood sheet Figure 124: Control joints for EIFS Figure 125: Bottom of cladding for EIFS Figure 126: Penetration for EIFS Figure 127: Window and door corner flashing for EIFS Figure 128: Windows and doors in EIFS Figure 129: Enclosed balustrade-to-wall junction for EIFS Figure 130: Parapet with metal capping for EIFS 162 164 166 166

Amend 5 Aug 2011

168 169 170 170

Figures E2/AS2 Figure 4.1: Footing dimensions and general details Figure 5.11: Soffit to wall junction A) Flat soffit B) Angled soffitAmend 5 Aug 2011

181 182 183 183 184

Figure 5.12: Timber-framed gable to earth wall

12

1 August 2011


R e f e r en ce s E 2 /VM1 & AS1 /AS2 /AS3

EXTERNAL MOISTURE

ReferencesFor the purposes of New Zealand Building Code (NZBC) compliance, the Standards and documents referenced in this Compliance Document (primary reference documents) must be the editions, along with their specific amendments, listed below. Where these primary reference documents refer to other Standards or documents (secondary reference documents), which in turn may also refer to other Standards or documents, and so on (lower-order reference documents), then the version in effect at the date of publication of this Compliance Document must be used. Where quoted Standards New ZealandAmend 5 Aug 2011

Amend 4 May 2008

AS/NZS 1734: 1997 Aluminium and aluminium alloys Flat sheet, coiled sheet and plate AS/NZS 2269.0: 2008 Plywood Structural NZS 2295: 2006 Pliable, Permeable Building Membranes

AS1 4.3.2, 8.3.4.3, 8.4.3.3, 9.6.3.3 AS1 8.5.3, 9.3.6.1, 9.8.2 AS1 8.1.5, Table 23 AS1 4.2.1, 8.3.4.1, 8.3.4.2, 8.3.4.3, 8.4.3.1,8.4.3.3, 9.6.3.1, 9.6.3.3, Table 20 AS1 4.3.10, 9.2.4 AS1 9.3.6.2, 9.5.2, 9.7.2 AS1 9.1.10, 9.4.2, 9.4.9, 9.7.3, 9.8.2, 10.2,Table 23 Definitions, VM1 1.1, 1.2, AS1 1.1, 1.3, 4.1.3, 4.2.1, 7.2.1, 8.3.4.1, 8.4.3.1, 8.5.1, 9.1.3.1, 9.1.3.5, 9.2.1, 9.2.3, 9.2.7.1, 9.2.9, 9.3.2, 9.6.3.1, Table 1, Table 2, Table 4, Table 5, Table 6, Table 18, Table 18A, Table 20 and Table 24 AS2 Figure 5.11 a) and b) AS1 9.4.1.1 AS1 8.1.1

Amend 2 Jul 2005

Amend 5 Aug 2011

AS/NZS 2728: 2007 Prefinished/prepainted sheet metal products for interior/exterior building applications Performance requirements AS/NZS 2904: 1995 Damp-proof courses and flashings AS/NZS 2908: Part 2: 2000 NZS 3602: 2003 Cellulose-cement products Flat sheet Timber and wood-based products for use in building

Amend 5 Aug 2011

NZS 3604: 2011

Timber framed buildings

Amend 4 May 2008

Amend 5 Aug 2011

NZS 3617: 1979

Specification for profiles of weatherboards, fascia boards, and flooring

AS/NZS 4020: 2005 Testing of products for use in contact with drinking water

Amend 5 Aug 2011


1 August 2011

13

EXTERNAL MOISTURE

R eferences E2/V M1 & A S 1/A S 2/A S 3

Where quoted

Amend 5 Aug 2011

NZS 4206: 1992 Concrete interlocking roofing tilesAmend 5 Aug 2011

AS1 8.2.1, 8.2.3 VM1 1.2, AS1 9.1.10 AS1 8.3.3

NZS 4211: 2008 Specification for performance of windows NZS 4217 Pressed metal tile roofs Part 1: 1980 Specification for roofing tiles and their accessories Part 2: 1980 Code of practice for preparation of the structure and the laying and fixing of metal roofing tiles

Amend 5 Aug 2011

SNZ HB 4236: 2002 Masonry veneer wall cladding NZS 4251: Solid plastering Part 1: 2007 Cement plasters for walls, ceilings and soffits AS/NZS 4256 Plastic roof and wall cladding materials Part 2: 1994 Unplasticized polyvinyl chloride (uPVC) building sheets

Definitions, AS1 Table 3 AS1 9.3.2, 9.3.4.1, 9.3.4.2, 9.3.6.1, 9.3.6.2 AS1 4.3.1 VM1 1.1, 1.4, 1.4.2, 1.4.3, 1.4.4 AS2 5.1.8, 9.7.2, Figure 4.1, Figure 9.2 a), b), c) and d) AS2 1.0, 1.1 AS2 Figure 4.1

Amend 5 Aug 2011

Amend 5 Aug 2011

AS/NZS 4284: 2008 Testing of Building Facades NZS 4298: 1998 Materials and workmanship for earth buildings Amend: 1 NZS 4299: 1998 Earth buildings not requiring specific design Amend: 1 NZS 4431: 1989 Code of practice for earth fill for residential development Amend: 1 AS/NZS 4534: 2006 Zinc and zinc/aluminium-alloy coatings on steel wire AS/NZS 4680: 2006 Hot-dip galvanized (zinc) coatings on fabricated ferrous articles AS/NZS 4858: 2004 Wet area membranes

Amend 4 May 2008

AS1 9.1.8.5 AS1 9.9.4.1, Table 20 AS1 9.7.7.1, 9.9.4.4, 9.9.10.1

Amend 5 Aug 2011

Amend 5 Aug 2011

14

1 August 2011


R e f e r e n ce s E 2 /VM1 & AS1 /AS2 /AS3

EXTERNAL MOISTURE

Where quoted Standards Australia AS 1366 Rigid cellular plastics sheets for thermal insulation Part 3: 1992 Rigid cellular polystyrene Moulded (RC/PS-M) Part 4: 1989 Rigid cellular polystyrene Extruded (RC/PS-E)Amend 5 Aug 2011

AS1 9.9.3.1 AS1 9.9.3.1 AS1 Table 20 AS1 4.3.6 AS1 4.3.7 AS1 8.2.1 AS1 8.2.3

AS 1397: 2001 Steel sheet and strip Hot-dip zinc-coated or aluminium/zinc-coated AS 1566: 1997 Copper and copper alloys Rolled flat products AS 1804: 1976 Soft lead sheet and strip AS 2049: 2002 Roof tiles AS 2050: 2002 Installation of roof tiles AS 3566 Self-drilling screws for the building and construction industries Part 2: 2002 Corrosion resistance Guide to the properties of paints for buildings

Amend 5 Aug 2011

AS1 8.4.8, 8.4.9, 9.6.6, Table 20 AS1 9.3.7, 9.4.9, 9.5.6, 9.7.3.1, 9.7.4, 9.8.9, 9.9.3, 9.9.6.3

Amend 5 Aug 2011

AS 3730

Amend 5 Aug 2011

Part 6: 2006 Solvent-borne Exterior Full gloss enamel Part 7: 2006 Latex Exterior Flat Part 8: 2006 Latex Exterior Low-gloss Part 9: 2006 Latex Exterior Semi-gloss Part 10: 2006 Latex Exterior Gloss AS 4046 Part 9: 2002 BS 6538: 1987 Part 3: 1987 Methods of testing roof tiles Determination of dynamic weather resistance Air permeance of paper and board Method for determination of air permeance using the Garley apparatus Zinc and zinc alloys. Specification for rolled flat products for building VM1 2.1, AS1 8.2.3 AS1 Table 23

Amend 2 Jul 2005

Amend 5 Aug 2011

British Standards Institution

Amend 5 Aug 2011

BS EN 988: 1997

AS1 4.3.8


1 August 2011

15

R e f e r e n c e s E 2 / V M1 & AS1 /AS2 /AS3

EXTERNAL MOISTURE

Where quoted American Society for Testing and Materials

Amend 5 Aug 2011

ASTM C1549: 2009 Standard Test Method for Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer ASTM D1667: 2005 Standard Test Specification for Flexible Cellular Materials Vinyl Chloride Polymers and Copolymers (Closed-Cell Foam) ASTM D2240: 2005 Standard Test Method for Rubber Property ASTM D6134: 2007 Standard Specification for Vulcanised Rubber Sheets Used in Waterproofing Systems ASTM E96: 2005 Standard Test Methods for Water Vapour Transmission of Materials

AS1 2.4

Amend 5 Aug 2011

AS1 9.1.10.7

Amend 5 Aug 2011 Amend 5 Aug 2011

AS1 9.1.10.7 AS1 4.3.9, 8.5.4 AS1 Table 23 AS1 10.3.2

Amend 5 Aug 2011

ASTM E104: 2002 Standard Practice for Maintaining Constant Relative Humidity by Means of Aqueous SolutionsAmend 5 Aug 2011

ASTM E2098: 2000 Standard Test Method for Determining Tensile Breaking Strength of Glass Fibre Reinforcing Mesh for Use in Class PB Exterior Insulation and Finish Systems (EIFS), after Exposure to a Sodium Hydroxide Solution ASTM E2134: 2001 Standard Test Method for Evaluating the TensileAdhesion Performance of an Exterior Insulation and Finish System (EIFS)Amend 5 Aug 2011

AS1 9.9.3.2

AS1 9.9.6

ASTM G154: 2006 Standard Practice for Operating Fluorescent Light Apparatus for UV Exposure of Nonmetallic Materials ASTM G155: 2005 Standard Practice for Operating Xenon Arc Light Apparatus for UV Exposure of Nonmetallic Materials Building Research Association of New Zealand BRANZ Bulletin 330: 1995 Thin flooring materials 2 Preparation and laying. Appendix 1 BRANZ EM 4: 2005 Evaluation method for jointing systems for flush finished fibre cement sheet BRANZ EM 5: 2005 Evaluation method for adhesives and seam tapes for butyl and EPDM rubber membranes BRANZ EM 6: 2010 Evaluation method for window and door support mechanisms or bars BRANZ Bulletin 411: 2001 Recommended timber cladding profiles

AS1 9.1.10.7 AS1 9.1.10.7

Amend 5 Aug 2011

Amend 5 Aug 2011

AS1 10.3.2 AS1 9.7.4, 9.7.10.2 AS1 8.5.4 AS1 9.1.10.5 AS1 9.4.1.1

Amend 2 Jul 2005

Amend 2 Jul 2005 Amend 5 Aug 2011

16

1 August 2011


R e f e r e n ce s E 2 /VM1 & AS1 /AS2 /AS3

EXTERNAL MOISTURE

Where quoted SCION Measurement of moisture content of woodAmend 5 Aug 2011

AS1 10.3.1

Other OrganisationsAmend 5 Aug 2011

Federal Specification Elastomeric type, cold applied single component Standard for caulking, sealing, and glazing in buildings, TT-S-00230C building areas (plazas, decks, pavements), and other structures EIMA 101.91: 1992 EIFS Industry Members Association. Standard Guide for resin of resin coated glass fiber mesh in exterior insulation and finish systems (EIFS), Class PB. ICBO Evaluation ISO 9223: 1992 ISO 11600: 2002 Acceptance criteria for flashing materials Services Inc AC148 Corrosion of metals and alloys; corrosivity of atmospheres; classification Building Construction Jointing products Classification and requirements for sealants 9.5.3.2, 9.6.7, 9.9.3,

AS1 4.5.2, 8.4.11.1, 9.1.6, 9.1.9.3, 9.2.8.2, 9.5.3.2, 9.6.7, 9.9.3, 9.9.8 AS1 9.9.3.2

AS1 4.3.11, 9.1.5, 9.9.4.4 AS1 4.2.1, 8.3.4.1, 8.4.3.1, 9.6.3.1, Table 20 AS1 4.5.2, 8.4.11.1, 9.1.6, 9.1.9.3, 9.2.8.2, 9.5.3.2, 9.6.7, 9.9.3, 9.9.8 AS1 4.3.5 AS1 4.3, 4.5.1, 4.5.2, 8.1.6.2, 8.3.1, 8.4.1, 8.4.12, 8.4.14, 8.4.15, 8.4.16.2, 8.4.17 AS3 1.0

Amend 5 Aug 2011

Amend 5 Aug 2011

ISO/TS 15510: 2003 Stainless steels chemical composition New Zealand Metal Roof and Wall Cladding Code of Practice: 2008 New Zealand Metal Roofing Manufacturers Inc.

Amend 5 Aug 2011

Cement & Concrete Association of New Zealand CCANZ CP01Amend 5 Aug 2011

Code of Practice for weathertight concrete and concrete masonry construction


1 August 2011

16A

16B

D e f i n i tio n s

EXTERNAL MOISTURE

DefinitionsAmend 2 Jul 2005

This is an abbreviated list of definitions for words or terms particularly relevant to this Compliance Document. The definitions for any other italicised words may be found in the New Zealand Building Code Handbook. Air seal A continuous seal fitted between a window or door reveal and the surrounding wall framing to prevent the flow of air into the interior of the building. Anti-ponding board A board laid under the lowest row of concrete and clay roof tiles and supports the roof underlay. The board is sloped to ensure moisture under the tiles is directed to the exterior of the roof. Apron flashing A near flat or sloping flashing with a vertical upstand, used at junctions between roofs and walls. Attached garage A garage that shares a common wall or walls with a habitable building, and is enclosed by roof and wall claddings that are continuous with the habitable part of the building. Base metal thickness (BMT) The thickness of the bare or base metal before any subsequent coating, such as galvanizing. Birds beak A double fold applied to the edge of a horizontal metal flashing to stiffen the edge and to assist in deflecting moisture away from the cladding system below. Refer also Kick-out and Drip edge.COMMENT: A birds beak is used at the bottom of a capping to deflect water away from the enclosed balustrade cladding. COMMENT: Cantilevered decks are often constructed by extending framing members through the cladding beyond the building face. Cantilevered decks are sometimes known as balconies.

Amend 2 Jul 2005

Capping A flashing formed to cover the top of an enclosed balustrade or parapet. Also known as a coping. Cavity batten A vertical packing member used to create a drained cavity as part of a cladding system. Cavity wall A term used to describe a wall that incorporates a drained cavity. Cavity spacer A short block used to provide intermittent support for fixings or pipe penetrations through a drained cavity, while not interrupting drainage within the cavity. A cavity spacer is required to be set to a slight fall (5 minimum from horizontal) to allow drainage of any moisture from the top. Cladding The exterior weather-resistant surface of a building.COMMENT: Includes any supporting substrate and, if applicable, surface treatment.

Amend 5 Aug 2011

Cladding system The outside or exterior weather-resistant surface of a building; including roof cladding and roof underlays, wall cladding and wall underlays, and cavity components, rooflights, windows, doors and all penetrations, flashings, seals, joints and junctions. Where required by this Acceptable Solution, the cladding system shall include a drained cavity. Control joint A joint designed to prevent damage by accommodating movement. See also Expansion joint. Damp-proof course (DPC) A strip of durable vapour barrier placed between building elements to prevent the passage of moisture from one element to another.

Amend 5 Aug 2011

Amend 5 Aug 2011

Butt flashing A preformed wall flashing, used to flash windows and corners on horizontal profiled metal wall cladding. A butt flashing is shaped to underflash the cladding, with the cladding butting against the exposed box portion of the flashing. Cantilevered deck A deck where no support is provided at the outer extremities of the deck.

Amend 5 Aug 2011


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17

EXTERNAL MOISTURE

D efinitions

Amend 5 Aug 2011

Damp-proof membrane (DPM) A sheet material, coating or vapour barrier, having a low water vapour transmission, and used to minimise water and water vapour penetration into buildings. Usually applied against concrete in contact with the ground. (Also known as a concrete underlay.) Deck An open platform projecting from an exterior wall of a building and supported by framing. A deck may be over enclosed internal spaces, or may be open underneath. Refer also Enclosed deck. Also known as a balcony. Direct fixed A term used to describe a wall cladding attached directly to the wall framing, without the use of a drained cavity. Dormer or dormer window A framed structure that projects from a sloping roof, and has a window at its outer end. Drained cavity A cavity space, immediately behind a wall cladding, that has vents at the base of the wall. Also known as a drained and vented cavity and referred to in this Acceptable Solution as a cavity or drained cavity. A drained cavity assists drying by allowing water which occasionally penetrates the wall cladding system to drain to the exterior of the building, and any remaining moisture to dry by evaporation. Where this Acceptable Solution requires a nominal 20 mm drained cavity, the depth shall be between limits of 18 mm and 25 mm.

EIFS (Exterior Insulation and Finish System). A polystyrene sheet-based cladding system that uses mesh reinforced polymermodified cement-based or polymer-based plaster base coats and a protective top coating. Electrolytic corrosion Galvanic corrosion commonly resulting from the contact of two dissimilar metals when an electrolyte such as water is present. Enclosed balustrade A timber-framed barrier with cladding across all exposed faces. Refer also Parapet. Enclosed deck A deck, whether over an interior or exterior space, that has an impermeable upper surface and is closed on the underside. May also be known as a balcony. Envelope complexity The categorisation of the complexity of the total building envelope into one of four classes, depending on the particular features of the building as specified in this Acceptable Solution. EPDM (Ethylene Propylene Diene Monomer) A thermosetting synthetic rubber used as a resilient part of a sealing washer, or as a roof membrane. Expansion joint A joint designed to prevent damage by accommodating movement. See also Control joint. External wall Any vertical exterior face of a building consisting of primary and/or secondary elements intended to provide protection against the outdoor environment.Amend 5 Aug 2011

Amend 5 Aug 2011


Amend 2 Jul 2005

For definition of masonry veneer cavity refer to SNZ HB 4236. Drip edge Fold(s) applied to the edge of a horizontal metal flashing to deflect moisture away from the cladding system below. Refer also Birds beak and Kick-out.

Amend 5 Aug 2011

Dwang A short (usually horizontal) member fixed between framing timbers. Also known as nogging. Eaves That part of the roof construction, including cladding, fascia and eaves gutter (spouting), that extends beyond the exterior face of the wall.

Finished ground level (FGL) The level of the ground against any part of a building after all backfilling and/or landscaping and/or surface paving has been completed. Flashing A component, formed from a rigid or flexible waterproof material, that drains or deflects water back outside the cladding system. Flexible flashing tape A flexible self-adhesive waterproof tape. Usually used as an accessory for wall underlays, to seal corners and intersections.D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G

Amend 5 Aug 2011

Amend 5 Aug 2011

Amends 2 and 5

18

1 August 2011

D e f i n i tio n s

EXTERNAL MOISTURE

Flush-finished The description of a cladding and joints system which relies on a protective coating applied to the face of the cladding to prevent the penetration of water. Framing Timber members to which lining, cladding, flooring, or decking is attached; or which are depended upon for supporting the structure, or for resisting forces applied to it. Hem A flat fold, not completely closed, applied to the edge of a metal flashing. Hidden gutter A gutter located within the boundaries of the roof framing. Hidden gutters may also be known as secret gutters or internal gutters. See also Valley gutters.COMMENT: Hidden gutters are distinct from gutters or spouting that are externally located beyond the bounds of the roof and wall framing.

Parapet A timber-framed wall that extends above the level of the roof cladding. Refer also Enclosed balustrade. Purlin A horizontal member laid to span across rafters or trusses, and to which the roof cladding is attached. Rafter A framing timber, normally parallel to the slope of the roof, providing support for sarking, purlins or roof cladding. Risk matrix A table that allows the calculation of a risk score by the allocation and summing of scores for a range of design and location factors applying to a specific building design. Risk score An aggregated numerical score for a proposed building as defined by this Acceptable Solution. The risk score is determined by completion of the risk matrix. Roof That part of a building having its upper surface exposed to the outside and at an angle of 60 or less to the horizontal. Roof underlay An absorbent permeable building paper that absorbs or collects condensation or water in association with roof cladding performance. Saddle flashing A flashing used to weatherproof the junction between a horizontal and vertical surface. Scupper An opening in a parapet or enclosed balustrade to allow water to drain into a rainwater head. Sill support bar A bar or mechanism complying with EM6, E2/VM1 tests, and Clause B2 of the Building Code, and used to support the weight of aluminium window and door joinery that is installed over drained cavities. Soft edge A compatible soft edging seamed onto flashings to provide closure to profiled cladding. Specific design Design and detailing for compliance with the Building Code, of a proposed part or parts of a building which are not shown in this Acceptable Solution.

Amend 5 Aug 2011

Hook An open fold applied to the edge of a metal flashing.COMMENT: A hook is distinct from a hem, as it is open at an acute angle rather than flattened.

Amend 5 Aug 2011

Kick-out A single fold applied to the edge of a horizontal metal flashing to deflect moisture away from the cladding system below. Refer also Birds beak.COMMENT: A kick-out is used at the bottom of a capping or other flashing to deflect water away from the cladding below.

Amend 5 Aug 2011

Lining The rigid sheet covering for a wall, ceiling or other interior surface. Masonry tiles Clay or concrete tile roof cladding. Masonry veneer Clay or concrete block veneer cladding. Membrane A non-metallic material, usually synthetic, used as a fully supported roof cladding, deck surface or, in conjunction with other claddings, as gutters or flashings.Amend 5 Aug 2011

Amend 5 Aug 2011

Amend 5 Aug 2011

NZBC New Zealand Building Code. Parallel flashing A roof flashing that runs along the roof slope, parallel to the roof cladding profile. Also known as a longitudinal flashing.D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G

Amend 2 Jul 2005

1 August 2011

19

EXTERNAL MOISTURE

D efinitions

Stanchion A connecting device, fixed into the structure of a building, that provides support for handrails, aerials and similar structures. Stopend A turn-up at the upper edge of profiled metal cladding, or at the end of gutters and some types of flashings.COMMENT: A stopend assists the control of moisture by ensuring any moisture reaching the edge of the roofing is deflected from further entry.

Waterproof and waterproofing The complete and total resistance of a building element to the ingress of any moisture. Weathertightness and weathertight Terms used to describe the resistance of a building to the weather. Weathertightness is a state where water is prevented from entering and accumulating behind the cladding in amounts that can cause undue dampness or damage to the building elements.COMMENT: The term weathertightness is not necessarily the same as waterproof. However, a weathertight building, even under severe weather conditions, is expected to limit moisture ingress to inconsequential amounts, insufficient to cause undue dampness inside buildings and damage to building elements. Moisture that may occasionally enter is able to harmlessly escape or evaporate.

Storey That portion of a building included between the upper surface of any floor and the upper surface of the floor immediately above, except the top storey shall be that portion of a building included between the upper surface of the topmost floor and the ceiling or roof above. Stucco A wall cladding system formed from reinforced solid plaster over a rigid or nonrigid backing. Stud A vertical framing timber. Transverse flashing A roof flashing that runs across the roof slope, at right angles to the roof cladding profile. Trapezoidal A type of profiled metal cladding with symmetrical or asymmetrical crests, with troughs between the crests. Trough profile A type of profiled metal cladding comprising vertical ribs with flat, or lightly profiled pans between the ribs. Also known as ribbed, secret fixed or tray profile. Underlay The material used behind a roof or wall cladding. Refer Wall underlay and Roof underlay. Valley gutter A gutter running down the valley formed by the intersection of two pitched roof surfaces.Amend 5 Aug 2011 Amend 5 Aug 2011

Wetwall The exterior cladding on a wall with a drained cavity. Wind zone Categorisation of wind force experienced on a particular site as determined in NZS 3604, Section 5.COMMENT: Maximum ultimate limit state speeds are: Low wind zone = wind speed of 32 m/s Medium wind zone = wind speed of 37 m/s High wind zone = wind speed of 44 m/s Very high wind zone = wind speed of 50 m/s Extra high wind zone = wind speed of 55 m/s. Specific design is required for wind speeds greater than 55 m/s.

Amend 5 Aug 2011 Amend 2 Jul 2005

Amend 5 Aug 2011

Wall refer External wall. Wall underlay A building paper, synthetic material or rigid sheathing used as part of the wall cladding system to assist the control of moisture by ensuring moisture which occasionally penetrates the wall cladding is directed back to the exterior of the building.1 August 2011 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G

20

Ve r i f i ca tio n Me th o d E 2 /VM1

EXTERNAL MOISTURE

Verification Method E2/VM11.0 Cladding systems of buildings, including junctions with windows, doors and other penetrations d) may include buildings based on (a), (b) and (c) above, but with specific engineering design frame elements of at least equivalent stiffness to the framing provisions defined in NZS 3604. 1.2.2 This Verification Method may also be used for individual buildings that comply with (a) to (d) above, and that are designed for a specific wind pressure up to a maximum ultimate limit state (ULS) of 2500 Pa.COMMENT: While the test specimens used for this Verification Method may include window and door units, it is only the junctions of these elements with other cladding elements that are assessed in the test.

1.1

General

This Verification Method is for determining compliance with NZBC E2.3.2 of cladding systems and associated window and door junctions only, for buildings of importance Levels 1 or 2 as described in Table 1.1(a) of NZS 3604. The tests in this Verification Method shall be undertaken in a test facility with IANZ or equivalent accreditation for testing the weathertightness of claddings to the procedures of AS/NZS 4284, and as used to establish the performance criteria detailed in Paragraph 1.4 Test Procedures.COMMENT: The weathertightness testing of AS/NZS 4284 is modified in this Verification Method for generic domesticoriented cladding because the Standard was developed primarily for testing specific, non-absorptive facades and curtain wall systems on high-rise commercial buildings.

1.3

Specimen details

The minimum size of the wall cladding specimen to be tested shall be 2.4 m x 2.4 m. Any cladding system within an Extra High wind zone or subject to a specific design wind pressure up to ULS 2500 Pa that relies on this Verification Method shall have a rigid underlay installed in accordance with Paragraph 9.1.7 of E2/AS1. In either of these two circumstances, a rigid underlay is not necessary for the verification tests as a flexible wall underlay may suffice unless the cladding to be tested specifically includes a rigid air barrier as part of the specified system. If the cladding system is never to be used with building elements penetrating the exterior surface walls, then the specimen shall include the details from Class 1. In all other cases, specimens with the details of Class 2 shall be tested, where the classes are described below: Class 1: Cladding systems where only vertical joints are required, and having no penetrations through the cladding. Testing shall include vertical joints, internal and external corners of the external wall junctions, and footer and header termination systems. Class 2: All other cladding systems to be used within the scope of this document.Amend 5 Aug 2011

1.2

Scope

1.2.1 The scope of this Verification Method shall be restricted to buildings that: a) are in accordance with the scope of Paragraph 1.0 of E2/AS1, and within the wind zones covered by Section 5 of NZS 3604, and b) have claddings that include a drained and vented cavity of nominal 20 mm minimum depth with minimum ventilation opening of 1000 mm2 /m at the foot, including any claddings that require a rigid wall underlay in accordance with Paragraph 9.1.7.2 of E2/AS1, and c) include window and door units that are manufactured to comply with the relevant requirements of NZS 4211, and

Amend 5 Aug 2011


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21

EXTERNAL MOISTURE

Verification Method E2/V M1

Testing is to include representative samples of penetrating building elements or joints, and including vertical and horizontal control joints, internal and external wall junctions, windows and/or doors, electrical meter boxes, balcony drainage and parapet flashings, and footer and header termination systems, plus any other relevant details. To allow the observation of any water penetration, a proportion of the internal wall lining shall be made using transparent material of sufficient structural capability and similar airtightness to resist the applied wind pressures. Adjacent to critical elements where visual access is required, the wall underlay shall be cut through and fastened back onto the framing, with the transparent internal lining fully sealing the internal perimeter of the observation opening. It is required that at least 2% of the area of the wall underlay (or equivalent) be so removed. A 15 mm diameter round hole shall be formed in the internal lining below the window to simulate the effect of power points, light switches and other air leakage through the internal lining.

1.4.2 Series 1 Static Pressure Water PenetrationThe water penetration test by static pressure shall be conducted in accordance with Clause 8.5 of AS/NZS 4284 and at the maximum test pressure of 455 Pa.

1.4.3 Series 1 Cyclic Pressure Water PenetrationThe water penetration test by cyclic pressure shall be conducted in accordance with Clause 8.6 of AS/NZS 4284 and to the cyclic pressure of 455 910 Pa at the prescribed Stage 3, with the Stage 1 and Stage 2 tests deleted.

1.4.4 Series 2 'Water Management Testing'Paragraphs 1.4.2 and 1.4.3 shall be repeated, following the formation of 6 mm diameter holes through the wetwall as allowed in AS/NZS 4284 Clause 9.9 in at least 4 places, as noted below: a) Through the window/wall joint at 3/4 height of both window/door jambs, b) Immediately above the head flashing, c) Through the external sealing of the horizontal and vertical joints, and d) Above any other wetwall penetration detail. The introduction of defects is intended to simulate the failure of the primary weatherdefence/sealing. It must only penetrate to the plane of the back of the wetwall so the water management of the cavity can be assessed. 1.4.4.1 Immediately upon the conclusion of the Water Management Tests (within 30 minutes) (Paragraph 1.4.4), the layers behind the wetwall that support air pressure (including sealing in the window trim cavity) shall be removed, and any evidence of non-compliance (as defined in Paragraph 1.4.5.3) noted.

1.4

Test procedure

The Verification Method shall consist of the extended water penetration test methodologies of AS/NZS 4284, following a preconditioning pressure loading exposure.

1.4.1 PreconditioningApply a preconditioning loading to the external face of the test sample for a period of 1 minute of positive pressure, followed by a period of 1 minute of negative pressure (suction). The loading shall be 1515 Pa.COMMENT: As the ventilated cavity is subjected to the same applied pressure, it is necessary that the material serving as the air seal is able to sustain the same applied loading. Where the test wall is utilising a permeable wall underlay or membrane, the internal wall lining will be required to sustain the serviceability limit state (SLS) wind pressures.

Amend 5 Aug 2011

Amend 5 Aug 2011

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1 August 2011


Ve r i f i ca tio n Me th o d E 2 /VM1

EXTERNAL MOISTURE

1.4.5 Series 3 'Wetwall Test'1.4.5.1 Repeat Paragraph 1.4.3 with an air pressure of 50 Pa, applied across the wetwall only, for 15 minutes. 1.4.5.2 Non-compliance shall be the presence of water (as defined in Paragraph 1.4.5.3) after carrying out the tests in Paragraphs 1.4.2 and 1.4.3, and the subsequent 'water management' tests (or evidence of any water) on the removed surfaces of the cavity. 1.4.5.3 Water which is able to penetrate to the back of the wetwall through introduced defects and joints shall be controlled. It may contact battens and other cavity surfaces, but no water shall be transferred to the plane of the wall underlay, cavity air sealing or structural framing due to a design or systemic failure. Water that may arrive on the underlay due to an 'isolated blemish' may be disregarded. No water may drip through an airspace within the cavity where it is possible for water to impact on a surface in the cavity and splash onto the wall underlay. However, the spattering of water into the cavity through the introduced defects shall be ignored. During the Wetwall Test, water is allowed to spatter up from the footer flashing, provided it is not held above any cavity obstruction.

1.6

Pro-forma for test details

The pro forma attached as Appendix 1 to this Verification Method may be used to provide specifiers with a summary of test details and results.

2.0

Pitched roofing systems over a ventilated roof space of 15 pitch or more

2.1 AS 4046 Part 9 provides a Verification Method for determining compliance with NZBC E2.3.2 of any tiled roofing system of 15 pitch or more above a roof space (i.e. not a skillion roof). Compliance is based on comparison of performance with a control roofing system described in the Standard. Compliance is achieved where the water penetration is less than, or equal to, the control sample. This test is also a Verification Method for other ventilated roofing systems or skylights with a pitch of 15 or more above a roof space.

3.0

Skillion roofs and commercial and industrial roofingAmend 5 Aug 2011

1.5 Transition period for existing verification certificates as at 31 August 20111.5.1 E2/VM1, included in E2 Compliance Document Amendment 5, is effective from 1 August 2011. 1.5.2 E2/VM1, included in E2 Compliance Document Amendment 4, remains effective up to and including 30 June 2013, provided that any testing under E2/VM1 from 1 August 2011 must be under E2 Compliance Document Amendment 5. 1.5.3 From 1 July 2013, only E2/VM1 included in E2 Compliance Document Amendment 5 applies and supersedes all previous versions of the document.

3.1 No specific method has been adopted for verifying compliance of skillion roofs or commercial or industrial roofing with NZBC E2.3.2.

Amend 5 Aug 2011


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EXTERNAL MOISTURE

Verification Method E2/V M1

Appendix 1: Pro forma Test results shall be expressed in the following tabulated format within the usual Test Report of the particular test laboratory.Amend 5 Aug 2011

Series 1: Static Water Penetration Test pressure 455 Pa Duration 15 minutes Series 1: Cyclic Water Penetration Test pressure 455910 Pa Duration 5 minutes

Amend 5 Aug 2011 Amend 5 Aug 2011

Amend 5 Aug 2011

Series 2: Water Management Tests Static Water Penetration Test pressure 455 Pa Duration 15 minutes Series 2: Water Management Tests Cyclic Water Penetration Test pressure 455910 Pa Duration 5 minutes

Amend 5 Aug 2011

Series 3: Wetwall Test Static Water Penetration Test pressure 50 Pa Duration 15 minutes Additional water penetration requirements:

Comments:

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A c c e p ta b le So lu tio n E 2 /AS1

EXTERNAL MOISTURE

Acceptable Solution E2/AS1Amend 5 Aug 2011

1.21.0 Scope

Construction excluded

1.2.1 Outbuildings Outbuildings, such as stand-alone garages and other structures that are unlined, are outside the scope of this Acceptable Solution.COMMENT: Details contained in this Acceptable Solution can be used for outbuildings and unlined structures, but the requirements may be in excess of the minimum required by the Building Code. This is particularly the case in regard to unlined and uninsulated buildings, where a drained cavity is unlikely to be necessary. However, care must be taken, as some weathertight details depend on the presence of an internal lining to provide pressure equalisation behind the cladding.Amend 5 Aug 2011

Amend 2 Jul 2005

This Acceptable Solution covers the weathertightness of the building envelope. Notes shown under COMMENT, occurring throughout this document are for guidance purposes only and do not form part of this Acceptable Solution.

Amend 5 Aug 2011

1.1

Construction included

Amend 2 Jul 2005

The scope of this Acceptable Solution is limited to the materials, products and processes contained herein, for buildings within the scope of NZS 3604, and: a) Up to 3 storeys with a height measured from lowest ground level adjacent to the building to the highest point of the roof (except for chimneys, aerials and the like) of 10 m or less, and b) With floor plan area limited only by seismic and structural control joints, and

1.2.2 Spread of flame Buildings with drained cavities and spread-offlame requirements, as specified in NZBC C Clauses, are outside the scope of this Acceptable Solution. Cavities in such circumstances must be specifically designed for both weathertightness and spread of flame.COMMENT: Options could include the provision of a fire rated wall behind the battens, or breaking the cavity at each floor and providing a cavity flashing and fire stop at each level.

Amend 2 Jul 2005

Amend 5 Aug 2011

c) External walls that are vertical, and roofs that are 60 or less above the horizontal. Where buildings are based on NZS 3604, but require specific engineering design input, the framing shall be of at least equivalent stiffness to the framing provisions of NZS 3604.COMMENT: The floor plan limitations of NZS 3604 may be exceeded up to the point that specific design is required to accommodate seismic or wind movement. Beyond that point, specific design is required to demonstrate compliance with Clause E2 of the Building Code. Claddings also required to perform as bracing must comply with NZS 3604. Where a drained cavity is used, specific testing can be used to demonstrate that a cladding on cavity battens can provide the required bracing resistance.

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1.2.3 Acoustics Buildings with drained cavities and acoustic requirements, as specified in NZBC Clause G6, are outside the scope of this Acceptable Solution.COMMENT: Cavities in such circumstances must be specifically designed for both weathertightness and acoustic performance.

Amend 2 Jul 2005

Amend 2 Jul 2005

Amend 5 Aug 2011

1.1.1 Attached garagesAttached garages that are integral with the weathertightness envelope of the building are included within the scope of this Acceptable Solution. Refer to Paragraph 9.1.3.4.

1.3 Provisions for snowSpecific design for preventing the ingress of snow melt water is required when the open ground snow load Sg, as defined in NZS 3604, exceeds 1.0 kPa, and the roof is constructed in a way that is likely to cause a build-up of snow.1 August 2011

Amend 2 Jul 2005

Amend 5 Aug 2011

Amend 5 Aug 2011


25

EXTERNAL MOISTURE

A cceptable S olution E2/A S 1

COMMENT: Hidden gutters, parapets and skylights are examples of features within a roof design that are likely to cause a build-up of snow.Amend 2 Jul 2005

However, some additional work, such as extra fixings that penetrate flashings, can lead to details that need to be considered in terms of specific design. Additional or alternative details may be required that need supporting documentation or testing to demonstrate compliance in regard to weathertightness.

Amend 2 Jul 2005

1.4

Specific design

Amend 5 Aug 2011

Buildings, components or junction details not included or shown in this Acceptable Solution require specific design.

2.2

Materials

Materials used to construct the building envelope shall be: a) In accordance with the durability requirements of NZBC B2, b) Suitable for their end-use, location and environment as shown in Table 20, and

Amend 2 Jul 2005

Amend 5 Aug 2011

1.5

Qualifications

c) Compatible with adjoining materials as shown in Table 21 and Table 22.

Amend 2 Jul 2005

COMMENT:Amend 5 Aug 2011

2.3

Systems versus materials

Amend 5 Aug 2011

An understanding of the proper methods of design and installation and the importance of the correct construction sequence is essential if an NZBC compliant building is to be achieved. Adequate training by those designing and applying particular products and claddings is therefore highly recommended. The design, installation and alteration of claddings will be restricted work under the licensed building practitioner scheme, due to take effect in 2012. Until then, the use of licensed designers, builders and installers is optional. It is important that product suppliers, manufacturers and NZ agents (for imported products) ensure those handling and applying their products are adequately trained to do so, and that site managers oversee the correct integration of adjoining building elements to achieve a complete weathering system.

All building products shall be considered as part of a system, even if the components of that system are provided from different sources. Materials used to construct the building envelope shall be designed as a complete cladding system rather than as separate items.COMMENT: It is important that the compatibility and durability of the combination of materials is able to be demonstrated for any given application.

Amend 5 Aug 2011

Amend 5 Aug 2011

Amend 2 Jul 2005

Amend 5 Aug 2011

2.42.0 General

Cladding finish colours

2.1

Weathertightness

Cladding systems shall meet the requirements of NZBC E2.2 to E2.3.7, and the provisions of this Acceptable Solution are acceptable means of achieving this.COMMENT: Most manufacturers provide technical literature for their cladding materials and systems that include recommendations for design and installation.Amend 5 Aug 2011

Finish colours for flush-finished fibre cement sheet and EIFS shall have a reflectivity of 40% or more when measured in accordance with ASTM C1549.COMMENT: Dark colours cause claddings to reach higher temperatures, which results in more thermal expansion and a greater risk of cracking of joints in monolithic wall claddings. Risks of cracking are also associated with dark colours on painted timber wall claddings and trim. Expansion of metal roofing and flashings are affected by dark colours. Colour cards from some coating manufacturers may include reflectance values.

Amend 5 Aug 2011

Amend 5 Aug 2011

Manufacturers recommendations may include information additional to that shown in this Acceptable Solution.

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1 August 2011



EXTERNAL MOISTURE

Amend 5 Aug 2011

2.5

Maintenance general

3.0

Weathertightness Risk Factors

Maintenance shall be carried out as necessary to achieve the required durability of materials, components and junctions. The extent and nature of necessary maintenance is dependent on the: a) Type of cladding or components used, b) Position of cladding or components on the building, c) Geographical location of the building, and d) Specific site conditions.COMMENT: A deterioration in the appearance of the surface of a cladding does not necessarily relate to a deterioration in the weathertightness of the cladding.Amend 5 Aug 2011

COMMENT: Analysis of inspection reports from leaking buildings shows that a high incidence of leaks is associated with junctions within, and penetrations through, the building envelope. It also shows serious problems are more commonly associated with claddings that have limited capacity to drain and dry out any water that gets behind them, when a leak occurs. This Acceptable Solution addresses these problems in two ways: a) By providing details for common junctions and penetrations of the building envelope, and b) By classifying buildings within the scope of this document into risk categories, and requiring different cladding solutions depending on the risk score. Using the risk assessment, risk factors can be identified and changes may be made to a design to lower the risk score.

Amend 5 Aug 2011

2.5.1 Regular maintenance Regular maintenance of a building will include: a) Washing exterior surfaces, b) Inspecting surfaces and junctions, and repairing or replacing items when necessary, in order to preserve the weathertightness of the building. c) Maintaining clearances between cladding and external ground or paving as per Paragraph 9.1.3. d) Maintaining minimum 35 mm clearances between roofing and membrane decking, and wall cladding above

3.1

Establishing the risk

A risk assessment of the proposed design shall be carried out using a building envelope risk matrix. This allows the risks related to various features to be aggregated, resulting in a risk score for the design. Figure 1 shows the process that shall be followed in order to assess the risk. 3.1.1 Definitions of risk Table 1 sets out the definitions of risk levels relating to the location and design features of the building. 3.1.2 The risk score Table 2 sets out the risk matrix that shall be used to define the risk score for a building within the scope of this Acceptable Solution. A risk score is calculated for each external face of the building. Claddings are then selected from Table 3 according to the risk scores, or the highest risk score may be used for all walls.Amend 5 Aug 2011

Amend 5 Aug 2011

e) Maintaining finish coatings especially for stucco, EIFS and fibre cement claddings.COMMENT: Washing by rain removes most accumulated atmospheric contaminants, but sheltered areas, such as walls directly below eaves, are protected from the direct effects of rain and require regular manual washing. Some heavily textured surfaces will not be as effectively washed by rain as smoother surfaces, so will require more regular manual washing. However, it is important that high pressure water is not directed at sensitive junctions such as window surrounds and other flashings. Great care must be taken to avoid water being driven past anti-capillary gaps and flashings into the wall cavities.


1 August 2011

27

EXTERNAL MOISTURE


Amend 5 Aug 2011

Figure 1:

How to assess risk Paragraph 3.1 Suitably detailed drawings are required to assess weathertightness risk. This documentation may include a site plan, floor plans, elevations, details of junctions and penetrations, and the presence of features like decks and pergolas.

Step One: Obtain Detailed DrawingsAmend 2 Jul 2005

Amend 5 Aug 2011

3.3 Wall claddingsThe following wall cladding systems are covered in this Acceptable Solution: a) Masonry veneer b) Stucco c) Timber weatherboards Paragraph 9.2 Paragraph 9.3 Paragraph 9.4Step Two: Assess Each External Face Against Risk Factors Assess the drawings for each external face to determine the risk score for each risk factor. These are: Wind zone Number of storeys Roof/wall intersection design Eaves width Envelope complexity Deck design Refer Table 1.

d) Fibre cement weatherboards Paragraph 9.5Amend 2 Jul 2005

e) Profiled metal wall claddings Paragraph 9.6 f) Fibre cement sheet g) Plywood sheet h) EIFS Paragraph 9.7 Paragraph 9.8 Paragraph 9.9.Step Three: Complete the Building Envelope Risk Matrix Table

Amend 5 Aug 2011

Other wall claddings are outside the scope of this Acceptable Solution.

Complete the Building envelope risk matrix (Table 2) for each face of the building. It is possible for different elevations to have different risk scores.

Step Four: Determine Suitable Cladding

Consult Table 3: Suitable wall claddings to determine what cladding types are recommended with the risk score for each face. The cladding selected must be appropriate for the score on that face, but can be beyond the minimum required (i.e. cladding suitable for a higher score can be used).

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EXTERNAL MOISTURE

Table 1:

Definitions of risk levels Paragraph 3.1.1, Figure 1 Score(5) 0 0 1 2 2 Risk severity Low risk Medium risk High risk Very high risk Extra high risk Low risk Medium risk High risk Very high risk Low risk Medium risk High risk Comments Low wind zone as described by NZS 3604 Medium wind zone as described by NZS 3604 High wind zone as described by NZS 3604 Very High wind zone as described by NZS 3604 Extra High wind zone as described in NZS 3604 (4) One storey Two storeys in part Two storeys More than two storeys Roof-to-wall intersection fully protected (e.g. hip and gable roof with eaves) Roof-to-wall intersection partly exposed (e.g. hip and gable roof with no eaves) Roof-to-wall intersection fully exposed (e.g. parapets, enclosed balustrades or eaves at greater than 90 to vertical with soffit lining) Roof elements finishing within the boundaries formed by the exterior walls (e.g. lower ends of aprons, chimneys, dormers etc) Greater than 600 mm for single storey 451600 mm for single storey, or over 600 mm for two storey 101450 mm for single storey, or 451600 mm for two storey, or greater than 600 mm above two storey 0100 mm for single storey, or 0450 mm for two storey, or less than 600 mm above two storey Simple rectangular, L, T or boomerang shape, with single cladding type Moderately complex, angular or curved shapes (e.g. Y or arrowhead) with no more than two cladding types Complex, angular or curved shapes (e.g. Y or arrowhead) with multiple cladding types As for High risk, but with junctions not covered in C or F of this table (e.g. box windows, pergolas, multi-storey re-entrant shapes etc) None, timber slat deck or porch at ground floor level Fully covered in plan by roof, or timber slat deck attached at first or second floor level Enclosed deck exposed in plan or cantilevered at first floor level Enclosed deck exposed in plan or cantilevered at second floor level or aboveAmend 2 Jul 2005 Amend 2 Jul 2005 Amend 2 Jul 2005 Errata 2 Dec 2011

Risk Factor A: Wind zone

B: Number of storeys

0 1 2 4

C: Roof/wall junctions

0 1 3

5

Very high risk

D: Eaves width (1)(2)

0 1 2

Low risk Medium risk High risk

5 E: Envelope complexity 0 1

Very high risk Low risk Medium risk

Amend 2 Jul 2005

3 6

High risk Very high risk

F: Decks(3)

0 2 4 6

Low risk Medium risk High risk Very high risk

NOTES:Amend 2 Jul 2005

(1) Eaves width measured horizontally from external face of wall cladding to outer edge of overhang, including fascias and external gutters/spoutings. (2) Balustrades and parapets count as 0 mm eaves. (3) The term deck includes balconies, as described in the Definitions. (4) Buildings in Extra High wind zones require rigid underlays and drained cavities, refer to Table 3. (5) Refer also to Table 2.

Amend 2 Jul 2005

Errata 2 Dec 2011 Amend 5 Aug 2011


24 December 2011

29

EXTERNAL MOISTURE


Amend 5 Aug 2011

Table 2:

Building envelope risk scores Paragraph 3.1.2, Figure 1 Risk severity

Risk factor

LOW

MEDIUM

HIGH

VERY HIGH (1)

Subtotals for each risk factor

score

score

score

score

Amend 5 Aug 2011

Wind zone (per NZS 3604)(1) Number of storeys Roof/wall intersection design Eaves width Envelope complexity Deck design

0 0 0 0 0 0

0 1 1 1 1 2

1 2 3 2 3 4

2 4 5 5 6 6 Total risk score for use in Table 3:

(Enter the appropriate risk severity score for each risk factor in the score columns. Transfer these figures across to the right-hand column. Finally, add up the figures in the right-hand column to get the total risk score.)Amend 5 Aug 2011

NOTE: (1) For buildings in Extra High wind zones, refer to Tables 1 and 3 for rigid underlay and drained cavity requirements.

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EXTERNAL MOISTURE

Table 3:

Suitable wall claddings Paragraphs 3.1.2, 7.4, 9.1.1,9.1.7.2, 9.4.1.2, 9.4.1.3, 9.6, 9.6.1, Figure 1

Amend 5 Aug 2011

Risk Score from Table 2 Direct fixed to framing

Suitable wall claddings(1) Over nominal 20 mm drained cavity Claddings on parapets, enclosed balustrades, and in Extra High wind zones shall be installed over drained cavities.(5)(6)Amend 2 Jul 2005 Amend 5 Aug 2011

06

Amend 5 Aug 2011 Amend 2 Jul 2005 Amend 5 Aug 2011

a) Timber weatherboards all types b) Fibre cement weatherboards c) Vertical profiled metal corrugated and symmetrical trapezoidal (3) d) Fibre cement sheet(4) (Jointed finish) e) Plywood sheet a) Bevel-back timber weatherboards b) Vertical timber board and batten c) Vertical profiled metal corrugated only(3)(6)

a) Masonry veneer (2) b) Stucco c) Horizontal profiled metal(3) corrugated and trapezoidal only d) Fibre cement flush-finished e) EIFS a) b) c) d) e) f) g) h) a) b) c) d) e) f) g) h) i) Masonry veneer (2) Stucco Horizontal profiled metal corrugated and trapezoidal only Rusticated weatherboards Fibre cement weatherboard Fibre cement sheet flush and jointed finish Plywood sheet EIFS Masonry veneer (2) Stucco Horizontal profiled metal corrugated and trapezoidal only Rusticated weatherboards Fibre cement weatherboards Fibre cement sheet flush and jointed finish Plywood sheet EIFS Bevel-back weatherboards

7 12


Amend 5 Aug 2011

13 20 a) Vertical profiled metal corrugated only(3)(6)

Amend 2 Jul 2005

Amend 5 Aug 2011

Amend 2 Jul 2005 Amend 2 Jul 2005

Over 20 a) Redesign the building to achieve a lower score, or b) Specific design The design may need changing to reduce the risk The building consent authority may require more comprehensive details and documentation providing evidence of weathertightness The building consent authority, designer or owner may require more inspections A third party audit of the design may be required.NOTES: (1) (2) (3) (4) (5) (6) The wall claddings in this table are limited to those covered in this Acceptable Solution. Traditional masonry veneer as per SNZ HB 4236, with minimum 40 mm cavity. Refer Figure 38 for profiles. Except stucco over a fibre cement backing. Claddings in Extra High wind zones require rigid underlays refer to Paragraph 9.1.7.2 Direct fix vertical corrugated steel is included as cavity construction.

Amend 5 Aug 2011


1 August 2011

31

EXTERNAL MOISTURE


3.4

Examples using the risk matrix

COMMENT: The house in this example is a simple single storey L shape and is considered low risk in terms of envelope complexity. The eaves are 500 mm wide, and the site is in a High wind zone. The covered porch is at ground level and so is considered low risk. For this example, the calculations have been done for the south elevation, and this face scores as very low risk. A similar risk score would result for all elevations of this building.

Paragraphs 3.4.1 to 3.4.3 provide examples that show a range of building styles. The completion of the risk matrix for each design is shown, together with the choice of wall claddings the risk scores indicate.COMMENT: The examples have been selected to show a range of design complexities, features and materials. Refer also to Guide to the Risk Matrix.

Amend 5 Aug 2011

3.4.1 Example 1 The first example illustrates the use of the risk matrix for a simple traditionally-styled building.

3.4.1.1

Cladding options

As all faces score low, cladding options from Table 3 are: a) Direct fixed claddings: i) Timber weatherboards all types shown ii) Fibre cement weatherboards iii) Vertical profiled metal corrugated and symmetrical trapezoidal only iv) Fibre cement sheet not flush-finished v) Plywood sheet b) Wall cladding with a nominal 20 mm drained cavity (note: claddings in Extra High wind zones require rigid underlays): i) Masonry veneer ii) Stucco iii) Horizontal profiled metal corrugated and trapezoidal only iv) Fibre cement flush-finished v) EIFS.Amend 5 Aug 2011

Figure 2:

Risk matrix example 1

Amend 5 Aug 2011


Amend 2 Jul 2005

Amend 5 Aug 2011

Table 4:

Risk matrix example 1 south face

Risk severityscore score score score

Risk factor

LOW

MEDIUM

HIGH

VERY HIGH

Subtotals for each risk factor 1 0 0 1 0 0 2

Wind zone (per NZS 3604) Number of storeys Roof/wall intersection design Eaves width Envelope complexity Deck design

0 0 0 0 0 0 0 0 0 0

0 1 1 1 1 2 1

1 2 3 2 3 4

1

2 4 5 5 6 6 Total risk score:

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EXTERNAL MOISTURE

3.4.2 Example 2Amend 2 Jul 2005

COMMENT: Overall the house in this example is still a relatively simple design with a single cladding type. It would be considered to be medium risk in terms of envelope complexity. The lean-to style room on the ground floor is quite simple but does introduce a roof-to-wall intersection which requires the correct flashing and particular care with the kick-out at the west end of the junction. This would make this factor very high risk. The timber deck, itself low risk, connects to the house at the first floor level, and so is considered to be medium risk. Any leaks at the connection points have an opportunity to enter the wall below. The eaves are less than 450 mm wide, and the site is in a High wind zone. The calculations have been done for the south elevation. The other elevations of this building score lower because they are simpler. The west elevation still has the deck connection and scores 7. Cladding options would be the same as for the south face. The east elevation scores 6 and the north elevation scores 5, so these have more cladding options.

The second example illustrates the use of the risk matrix for a moderately complex building.

Figure 3:


Amend 5 Aug 2011

Table 5:

Risk matrix example 2 south elevation

Risk severityscore score score score

Risk factor

LOW

MEDIUM

HIGH

VERY HIGH

Subtotals for each risk factor 1 1


0 0 0 0 0 0

0 1 1 1 1 2 1 2 1

1 2 3 2 3 4

1

2 4 5 5

5 2 1 2 12

Amend 5 Aug 2011

2

5 6 6 Total risk score:

Amend 5 Aug 2011

3.4.2.1 Cladding options south and west elevations Cladding options from Table 3, are: a) Direct fixed claddings: i) Bevel-back weatherboards ii) Vertical board and batten weatherboards iii) Vertical corrugated metal, and

Amend 2 Jul 2005

b) Wall cladding with a nominal 20 mm drained cavity: i) Masonry veneer (with 40 mm cavity) ii) Stucco iii) Horizontal profiled metal corrugated and trapezoidal only iv) Rusticated weatherboards v) Fibre cement weatherboards vi) Fibre cement sheet vii) Plywood sheet viii) EIFS.1 August 2011

Amend 2 Jul 2005

Amend 2 Jul 2005


33

EXTERNAL MOISTURE


3.4.2.2 Cladding options north and east elevations Cladding options from Table 3, for east and north faces, are: a) Direct fixed claddings: i) Timber weatherboards all types ii) Fibre cement weatherboards iii) Vertical profiled metal corrugated and symmetrical trapezoidal only 3.4.3 Example 3

iv) Fibre cement sheet v) Plywood sheet vi) EIFS, and b) Wall cladding with a nominal 20 mm drained cavity: i) Masonry veneer (with 40 mm cavity) ii) Stucco iii) Horizontal profiled metal corrugated and trapezoidal only.Amend 2 Jul 2005

Amend 2 Jul 2005

The third example illustrates the use of the risk matrix for a complex building.COMMENT: The combination of features present on the south elevation results in a very high risk score. The presence of a parapet at the roof, decks, enclosed balustrade-towall junctions and pergola connections all contribute to this risk. The site is in a High wind zone.Amend 2 Jul 2005

Figure 4:


The risk score is sufficiently high that the south elevation would require specific design, or redesign to lower the risk. Specific design may result in the building consent authority possibly: a) Needing more details to be provided, b) Requiring more inspections during construction, c) Requiring a third party audit of the design. The east and west elevations also score very highly at 18-20, and would require a cladding with a cavity such as vertical profiled steel, masonry veneer or any other cladding with a nominal 20 mm drained cavity. The north elevation scores 14, so would require the use of the same cladding option as the east and west elevations.

Amend 2 Jul 2005

Amend 2 Jul 2005

Amend 2 Jul 2005

Table 6:

Risk matrix example 3 south elevation

Risk severity Risk factor LOW MEDIUM HIGH VERY HIGH Subtotals for each risk factor 1 1 5 5 6 5 5 6 4 22score score score score


0 0 0 0 0 0

0 1 1 1 1 2 1

1 2 3 2 3 4

1

2 4 5 5 6

4

6 Total risk score:

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EXTERNAL MOISTURE

3.4.3.1 Cladding options south elevation As the south face scores over 20, it will require:Amend 2 Jul 2005

COMMENT: Generally, the durability requirements for flashings specified in B2 are: a) 50 years, where flashings are: i) completely hidden behind claddings such as masonry veneer, or ii) not accessible, b) 15 years, where flashings are: i) exposed, partially exposed, or ii) accessible. Two part flashings allow replacement of the flashing without cladding alteration. An example of a two part flashing is shown in Figure 7.Amend 2 Jul 2005

a) Specific design, or b) Redesigning the proposal to reduce the risk, so reducing the risk score. 3.4.3.2 Cladding options other elevations As the other faces score from 14 to 20, cladding options from Table 3 are: a) Direct fixed claddings: i) Vertical corrugated metal, and

Amend 2 Jul 2005

Amend 2 Jul 2005

b) Wall cladding with a nomi